Froth flotation of iron impurities from feldspar



Patented Sept. '27, 1949 FROTH FLOTATION OF IRON IMPURITIES FROM FELDSPAR Elmer William Gieseke,

assignor to American Old Greenwich, Conn., yanamid Company, New

York, N. Y., a corporation of Maine No Drawing. Application November 24, 1945, Serial No. 630,695

4 Claims. (Cl. 209-166) This invention relates to the beneficiation of ieldspars and feldspathic materials. In particular, it concerns an advantageous treatment of those ores of feldspathic materials in which ex- .cessive amounts of iron-bearing impurities must be reduced.

Feldspars and feldspathic materials, as used in the glass, pottery and other ceramic industries, are ordinarily subjected to specific limitations as to maximum iron content. This is done in order to eliminate undesired color which might be imparted to the finished articles by iron-bearing minerals during manufacture. The desired minerals are usually some form of aluminum-bearing silicates, accompanied in the ore by gangue comprising silica and other siliceous constituents, commonly iron-bearing. Therefore, in addition to the maximum iron limitations, a minimum alumina content is also frequently specified.

For these reasons the present invention may be considered as concerned with the separation of silica and iron-bearing silicates from non-ferrous silicates generally and non-ferrous aluminumsilicates specifically. Accordingly, in the present specification and claims the term feldspathic materials" is used to include ores of feldspar, aplite, nepheline-syenite, kyanite, sillimanite and the like in which a feldspathic non-ferrous silicate or non-ferrous aluminum silicate constitutes the desired constituen Reference to the undesirable constituents as iron minerals or as iron-bearing substituents is quite general in commercial practice. This is true even though such substituents may not be oxidized iron mineralsper se, although the latter, as for example in hematite, limonite, magnetite, ilmenite and the like are commonly present in varying amounts, ordinarily small. Most of the undesirable ferrous metal content is present in combination with other elements in silicates, particularly complex silicates containing in addition oxides such as those of lithium, potassium, barium, calcium, magnesium, aluminum and the like. In the present specification and claims, therefore, the expression "ferrous metal is used to designate only minerals containing iron as an essential constituent of the compositiomas for example in hematite or biotite, and iron-bearing is used to indicate a broad group including silicates such as pyroxenes, amphiboles, micas,

tourmaline, serpentine, and the like in which ferrous metal itself need not necessarily be a constituent but may be present. Small amounts of iron sulfide minerals such as pyrite and pyrrhotite also are frequently found.

Requirements as to maximum iron-bearing content and minimum aluminum content are becoming increasingly rigid. While abundant deposits of feldspathic materials are common, unfortunately it is becoming increasingly diflicult to find natural deposits which meet industrial specifications. Beneficiation operations, as by tabling, flotation and/or magnetic separation, are therefore becoming increasingly important considerations in commercial practice. For a number of reasons beneficiation by froth flotation is generally accepted as preferable where it can be used.

Howevenin the past the beneficiation of lower grade natural deposits by froth flotation has been found to be neither simple nor inexpensive. Anionic flotation with the usual types of fatty-acid, resin-acid or soap type promoter has been found ineffective in separating the desirable'from the undesirable silicates. While silica and some silicates, for example some clays, micas and the like, can be floated with a cationic type of reagent, the latter are not always one silicate from another.

Moreover, these reagents are not inexpensive,

are not particularly efiective on coarser sized particles and are extremely sensitive to slimes.

of their particular selectivity, carefully on an ore which has been properly ground and very completely deslimed. Desliming is so critical that the degree required may make the process economically impractical. Further, separation of some iron-bearing silicates, for example, iron-bearing tourmalines, biotite and the like from feldspar usually requires a sec- To take advantage ondary flotation and/or 1magnetic treatments.

While such methods, or a combination of them, can often be worked out to produce an effective separation, such procedures in practice are both complicated and expensive.

There remainstherefore a demand for a suitable operation, whereby the iron content may be reduced below the desired maximum in a simple, relatively-inexpensive operation and one which, if necessary, permits raising the aluminum coneffective in separating they must be used tent to a point above a specified minimum. Preferably also, the process should economically employ reagents which are readily obtainable and they should be used in a manner in which they are not hindered by the presence of slimes. It is, therefore, the principal object of the present invention to provide such a process together with suitable reagent combinations adapted to produce useful results when used therein.

Contrary to the most successful practice in the prior art of concentrating silica and silicates by froth flotation with a cationic promoter, followed if necessary by magnetic separation, the process of the present invention first employs an inexpensive, simple and effective anionic flotation of iron-bearing minerals from the feed. This is accomplished by using a promoter, comprising a suitable sulfonated organic compound in an acid circuit of the correct pH. To increase the aluminum content of the residual tailing,

which may contain excessive amounts of silica and non-ferrous silicates, this is followed, if so desired, by a cationic flotation in which a concentration of the non-ferrous, aluminum-bearing silicates is carried out. The effectiveness of this treatment is particularly remarkable when it is considered that the iron content in the feed is considerably lower than that of the flotation tailings obtained in any practical treatment of commercial iron ores.

The problems solved by the process of the present invention are well illustrated in the beneflciation of feldspar itself. Feldspar is usually considered to be an aluminum silicate containing oxides of sodium, potassium or calcium. .As found in natural deposits, feldspar minerals usually are accompanied by one or more impurities of a. wide range including quartz or silica, micaceous and/or ferrous metal silicates such as biotite tourmaline and the like, and also by high aluminum content silicates such as kyanite and spodumene. In addition, at least traces of iron oxide minerals such as hematite, limonite and the like are almost always present. The problem, then, is to reduce the content of silica and ferrous metal oxides or silicates while retaining as high a content as possible of the desirable nonferrous, aluminum silicates.

When an attempt is made to do this with ordinary anionic reagents of the fatty-acid, resinacid or soap type, little or no selectivity is found. Use of various depressants, froth modifiers, supplementary promoters and the like have not been found satisfactory in effectively modifying the action of the usual anionic promoters. Nevertheless, because an anionic flotation is usually one which is less sensitive to slimes and generally employs less expensive reagents, it is to be industrially preferred.

It is, then, a feature of the present process that it successfully employs anionic flotation. The novel anionic promoters used may be designated generally as sulfonated petroleum hydrocarbons. Three types have been found to be particularly useful: (1) the oil-soluble, waterinsoluble, water-dispersible, sulfonated petroleum hydrocarbons; (2) the water-soluble, sulfonated petroleum hydrocarbons of the green acid type; and (3) mixtures thereof.

Such sulfonated products are commercially available in a number of different forms. However, as shown, for example, in U. S. Patent 2,331,049, their principal source is as by-products from the refining of petroleum lubricating oil fractions in the course of treatment with fuming all sulfuric acids or sulfuric acids. when so produced, these by-products are generally found to be salts of the sulfonated hydrocarbons, most commonly the sodium salt although other salts may be encountered. In some cases no attempt has been made to neutralize the acid product.- Even after neutralization, free sulfonates and/or sulfates are often found.

In general, the oil-soluble, water dispersible group of sulfonatcs used are thosecharacterized as "mahogany sulfonates," or when neutralized with alkali, as "mahogany soaps," because of the characteristic color which is usually, though not necessarily, present in a solution thereof. The water-soluble products are derived from the water-soluble sulfonate portions which are separated from the same treatments. From their characteristic color which is normally present in solution, the water-soluble types are often designated as "green acids, or when neutralized as green soaps. They constitute an entirely different class of materials from the so-called kerosene acid sludge products. They differ not only in their different source, the refining of lubricating oils, but in appearing to have a much higher content of carbon atoms, apparently 18 or more and usually around 20-24 as compared with the 12-14 or less of the kerosene products, and even more importantly, in their effectiveness in use.

For many purposes in the process of the present invention it has been found desirable to use a mixture of both the mahogany and the green type of sulfonates. In this way it is possible to take advantage of the most useful properties of each to obtain a result which in seneral is better than either will produce when used alone.

Oil-soluble, water-dispersible, sulfonated petroleum hydrocarbons have been suggested for the concentration of non-metallic minerals, metallic sulfide minerals and certain oxidized metal ores. However, their direct substitution for such anionic promoters as resin acids, fatty acids, soaps and the like in an attempt to beneficiate feldspathic materials by the conventional anionic flotation of the prior art produces no particularly useful result. No useful separation of ferrousmetal silicates and/or silica from the desirable constituents is obtained. Nor is any better success obtained by trying as substitutes watersoluble, petroleum sulfonates of the green acid type, either alone or mixed with oil-soluble, water-dispersible sulfonates. It is a feature of the present invention that the effective separation of ferrous-metal silicates from the other constituents must be effected under acid conditions. Not only must the circuit be acidic but the degree of acidity must be controlled. If the pH is too high, for example, more than about 4.5 to 5.0 effective flotation of the ferrous-metal silicates may be obtained but in addition substantially all of the other silicates float therewith. On the other hand, if the pH becomes toolow, lower than about 2.5-2.8, the depressing action of the acid begins to be noticeable not only on the non-ferrous-metal silicates but also on the ferrous-metal silicates. Again no separation of any particular utility is obtained. It is important therefore that the pulp to be treated have a pH in the range of about 2.5 to 5.0 at

flotation densities. I

Any acid or acid-liberating compound which will produce the desired pH may be used. It

should be one which does not contain cationic point of view because of its low cost and availability. However, in some cases other acids such as hydrochloric or even acetic acid, because of particular local conditio may be economically competitive.

Both or either of the oil-soluble, water-dispersible sulfonates or the water-soluble sulfonates may be used in a crude or semi-refined or fully refined condition. Usually the only noticeable effect of purification is in relation to the amount which is required for a given flotation. The expression sulfonated" is generically used and does not exclude the presence of some of the sulfur in sulfate groupings since the latter are usually present, at least in small amounts. Similarly, the sulfonates may be wholly or partially neutralized, as with sodium, potassium or ammonium ions. All or part of the sulfonated material therefore may be present as a soap" or salt. The sulfonated compounds are those customarily used because of their availability. Similar compounds which are phosphoretted rather than sulfonated are highly successful in use. However, their practical utilization is limited by the lack of a commercial source.

The amount of such reagent used will obviously vary in accordance with a number of conditions. The principal variants are occasioned by the amount of the undesirable constituents which must be removed, the physical condition of these constituents, and the content of available sulfonated compound in the particular reagent used, i. e., the degree of purity. For normal operation it is usually found that the amount of reagent required will be equivalent to about 0.1 to 3.0 lbs/ton of ore treated. I

The larger amounts of reagent, even in some cases exceeding 3 lbs/ton, are usually found to be required when much of the undesirable material is present as slimes or when the ore to be beneflciated is particularly high in micaceous material. In such cases an economic balance will usually show that it is preferable to carry out a partial desliming operation, as by screening or hydraulic separation, before flotation, thereby reducing reagent consumption.

In some cases excessive reagent consumption also can be partially offset by the addition of an oiling agent. Particularly is this true in making use of the water-soluble sulfonates. In such a case the oiling agent not only aids in slimes control but also may act as a froth controlling agent and be of assistance in insuring a good separation. Substantially any oiling agent may be used. Probably the simplest, most readily available and cheapest are the petroleum hydrocarbon oils, as for example kerosene and fuel oils. If desired, however, these may be effectively replaced by saponifiable glycerlde oils such as corn oil, coconut oil,-fish oil and the like; or by higher certain fatty acids such as oleic acid and the like having oily characteristics or even by a fatty acid-resin acid mixture such as is found in talloel.-

Obviously the degree to which beneficiation can be effected and still have a useful recovery will depend to considerable extent on the nature of the iron-bearing constituent which is to be removed. In anore in which the iron-bearing constituent is relatively free or easily liberated, the extent to which it can be removed while still obtaining good recovery is quite high. Thus, for example, ores which may assay as high as 1.5-

, I 6 g 2.0% of F820: in a free, or readily freed, condition may be readily reduced to below the maximum required for even the highest grades. On the other hand, when much of the iron is present, for example, as micaceous silicates meeting such low limits of iron content in the eventual product is much more difficult to obtain with a high recovery.

Preferably, but not necessarily, treated should be conditioned with the reagents before being subjected to froth flotation. In so doing, better results are usually obtained if the conditioning is carried out on an aqueous pulp of the ore having a high solids content of 30-70% usually 50-60%. This pulp is then diluted to flotation density, usually before or during transfer to the flotation cell or cells. Where equipment is not available, acceptable results may usually be obtained by conditioning with the reagents at flotation density. Particularly is this true if the process water is recycled and reused. I good results maybe had even by adding the reagents directly to the flotation cells.

As noted above, it may be desirable to deslime the ore before conditioning it with the flotation reagents. It is, however, an advantage of the present process that this is not a limitation to the extent that it is in cationic flotation operations of the prior art. As noted above, the tendency of the presence of slimes is to increase reagent consumption and lower somewhat the eflectiveness of separation. Where it is determined that desliming is more economical than to permit high reagent consumption, simple desiliming, as by hydraulic classification, is usually adequate. conventionally used reagents such as soluble silicates, alkaline phosphates and the like may be used as dispersants if so desired.

Ferrous-metal minerals frequently are present in the materials as stains of hematite or the like. In preparing ore for desliming, a scrubbing in the presence of a strong alkali, using from about 0.5 to 1.5 lbs/ton of caustic, or the equivalent, is often desirable. This not only is helpful in dispersing the slimes but also assists in the separation of at least a part of the staining-iron.

The practice of the present invention will be EXAMPLE In order to illustrate the practice of the prior use soaps as a promotor' for silicate minerals in the presence of lime or other alkaline metalions, a sample of feldspar ore containing feldspar, quartz, mica, tourmaline and garnet and having considerable iron staining on the feldspar was ground, pulped with water to about 22% solids, conditioned for 1 minute with 3 lbsJton of lime and floated for 4 minutes with l lb./'ton of talloel sodium soap. Since it was apparent by visual observation that the full possibilities of concentration were not exhausted, 1 lb. of crude octadecylamine acetate was then added to the flotation cell and a second concentrate' the ore to beof the alui Table 1 Per CentAssay gfig g Per Cent Weight A110; F610: AhOs FerO Feed 100.0 18.08 0.112 100.00 100.00 0011011.. 42.7 15.62 0.248 41.48 01.03 000042.. 34.3 15.22 0.102 32.40 20.30 Rougher Tail 21.01 18.19 0.130 20.00 18.02

EXAMPLE 2 In order to show the effectiveness of the present process using sulfonated petroleum hydrocarbons in acid circuit, a series of tests was carried out on a feldspar ore which contained considerable quartz, mica and iron silicates. The ore was reduced to size for flotation feed, pulped to about 65% solids with water, and conditioned for 2 minutes with 0.60 lb./ton of sulfuric acid, 1.27 lbs/ton of fuel oil, 0.09 lb./ton of Aerofloat 31 and with a promotor. The latter were various sulfonated petroleum hydrocarbons as shown in the following table, which also summarizes the metallurgical results. In the table, promoter A is an oil-soluble, water dispersible sulionated petroleum hydrocarbon, and promoter B is essentially a water-soluble sulionated petroleum hydrocarbon of the green type containing about 20-24 carbon atoms. The Aerofloat 31 reagent used in this and subsequent tests comprises about 6% thiocarbanilid dissolved in dicresyl dithio phosphoric acid. As used in the process of the present invention it appears to have a beneficial effect on the froth quality.

From the foregoing table it will be seen that even when no particular attempt is made to obtain the best possible combination of steps, the reagent combination comprising about 25% oil-soluble, water-dispersible and 75% water-soluble petroleum sulfonates produced the best results. It should be noted, however, that the other reagent combinations are all definitely superior to the results obtained in Example 1. The results indicated in the above table were found to be generally applicable to the concentration of feldspar ores, i. e., mixtures containing from about 50% to about 85-or 90% of water-soluble sulfonates and from about 10 or to about 50% oilsoluble, water-dispersible sulfonates generally give better results. The exact proportions, however, vary somewhat with the amount of oiling 76 caustic soda.

agent used. Where in the following examples and claims a mixture of oil-soluble, water-dispersible and water-soluble petroleum sulfonates is indicated, a mixture within this range of 15 to 50% of oil-soluble sulfonates is that used.

TREATMENT OF STE-DIES AND STAINS Exsurm: 3

Percent S102 14.00 A1203 16.11 FeaOa 0.19 CaO 0.90 MgO (trace) K00 4.59 K10 4.59 No.10 4.34

In the first test the ore was reduced to a suitable size for froth flotation, pulped with water. and without further treatment conditioned at 68% solids for 2 minutes with 0.66 lb./t0n of H2804, 0.77 lb./ton of fuel oil, 0.05 lb./ton of Aerofioat 31 and 1.67 lbs/ton of mixed petroleum sulfonates, approximately 25% being oilsoluble, water-dispersible. The treated pulp was then reduced to flotation density and subjected to froth flotation for 3 minutes. Visual observation indicated that insuflicient iron was floated to be useful and the products were discarded.

EXAMPLE 4 Another sample of thesame ore. after being size reduced and pulped with water, was deslimed hydraulically in the presence of 0.135

lb./ton of caustic'soda. The deslimed sands were then conditioned in the same way with the same reagents as in Example 3 and given the same flotation. The results are shown in the followin Table I171.

of treating the ore with caustic soda and desliming prior to flotation.

EXAMPLE 5 A third sample of the same ore, after being size reduced and pulped to about 64% solids, was scrubbed for 2 minutes with 0.13 1b./ton of caustic soda in a flotation machine with the air inlet closed. The treated pulp was then deslimed hydraulically and the sands conditioned and floated with the same reagents and in the same way as in Examples 3 and 4. As shown in the following Table IV, the results are considerably better than simple desliming in the presence of Presumably. but not necessarily.

- g on the iron staining.

this is due to the eflect of the scrubbing action was subjected to froth flotation for 4 minutes and the concentrate collected. Sample B was then treated in the same manner but the amount water-dispersible, and water-soluble petroleum sulfonates. After dilution to about 29% the pulp Table? of petroleum sulfonates was increased to 1.12 5 lbs/ton. Sample 0 was also treated in the same m yg rer Dl ggil tign, way but using 1.67 lbs/ton oi the mixed petroreagent leum sulfonates. The metallurgical results are Fe 0 A] o 1 7: shown in Table V It will be noted from Table I 1 l V that because of the acidic nature of these mo 00 16 u o 25 10 particular sulfonates, varying the amount there- 12277 10 of has an effect on the pH of the pulp. When 04.00 14.50: 0.053 70.41 17.02 this occurs in plant practice where the pH is t controlled it must be allowed for in regulating EXAMPLE 6 amounts of acid to be added. It will also be noted that while the recovery of iron in the con- ...iiz szztil t s.0.101110301121201; 0 0 1 0 0 0 001 t I t or ampe e aum na assay 0 e all of "02. 0.1020;treatments:023 00 r t t tr010 on s s y o promoer o e eween and 1.6 lb./ton of sulfuric acid rather than the caustic 20 lbs/ton in the case of this particular ore. Ordi-' soda was used in the scrubbing treatment. The narily, however, the lower iron content in the' results were very poor and the products were tailing is more important at this stage than the discarded Without an lyz ng them. question of recovery. In plant practice, there- The observations obtained in the preceding fore, the resultsobtained with Sample C wouldtests were found generally applicable to the beneprobably be preferableas producing a tailing asiiciation of feldspar ores in which there is appresaying less than 0.1% of F8203.

Table V AS8233, Per Dilstributim,

l 11 801111110 i gfi fi ptt iv? 0e F010: A100: A1001 F0101 A. 0.33 5.2 (Poor float-ciscarded 1 000---- 100.00 0.25 10.11 100.00 0.00 B 1.12 4.0 00110.... 1.41 1.88 55.02 Tail..-" 00.00 0.10 15.20 00. 05 31.35 300---- 100.00 0.32 10.11 100.00 100.00 0 1.67 4.0 00110-..- 8.94 2.64 75.40 Tail 00.12 0.00 15.20 04.10 21.12

ciable iron staining and/or in which there 1 18 118 EXAMPLE 3 v considerable excess of micaceous silicates. e scrubbing with caustic soda followed by desllmggdggfi g g g E fgfi g gg g'gg s i fg ing is generally found to produce better results Example 7' sample was repeated on additional than straight desliming either with or without samples the Ore except that different alkalL swubbmg m t if of acid in amounts of acid were present during the conera'l proved to be rather ne ec ditioning operation. The conditions otherwise EFFECT OF VAR A N DH AND AMOUNT were identical to those in the treatment of OF PROMOTER 0N RON FLOTATION Sample C. The results are shown in the follow- EXAMPLE 7 ing Table VI. It also will be seen therefrom that while, within limits, a continued decrease in, gg g g 122;: 23 igii g i g g ggg the F8203 content 01 the tailing can be effected, were carried out in which additional samples of it is done at the expense the A1203 content the same ore treated in Examples 3 to 6 were. Therefore the amount of ac.1d used must sidered from the point of view of the maximum scrubbed with caustic soda and deslimed as in Example 5. Sample A was conditioned at about F9293 penmtted by the speclficatlons to be 05-10% solids with 0.33 115 0011 of sulfuric acid, Ordmarily, lmwever, as abme 9 mm 0.11 111 0011 of fuel 011 (22 315.), and 0.50 111 0011 content is pteferable to hlgh recovery m of an approximately 1-3 mixture of oil-soluble, treated ore is both cheap and unsaleable. In

most plant operations the results obtained on Sample E would be preferred.

Table VI H8O P t Assayapercent Distribution 1 4 81' 0911 Sam? lb./ton' Wt.

A: FezOs A1200 ezOa D 0 (P0orfl0atd1scarded) eed 100.00 10.11 0.32 100.00 100.00 0 0.03 00110 .8.94 2.04 15.40 TaiL s0. 12 10. 23 0.08 84. 10 21. 12 Feed 100.00 10.11 0.20 100.00 100.00 E 0.66 Gonc 12.77 1.50 76.10 Tail 04.50 14.50 0.05 70. 41 11.02

To illustrate further that sufllcient acid to activate the ferous metal silicates must be used but excessive amounts do little if any good, the following tests on another ore of similar type were conducted. Samples were ground to suitable size, pulped with water to about 60% solids, scrubbed for two minutes with 0.133 lbs/ton of NaOH and deslimed hydraulically. Four samples were then conditioned for two minutes at about 60-70% solids with 1.11 lbs/ton of the mixed sulfonates used in Examples '7 and 8,. 0.77 lbJton of fuel oil (22 B.) and varying amounts of H2804. The pulp was then diluted to about 27% solids, subjected to froth flotation, the concentrate removed and the rougher tailing collected. The results are shown in Table VII.

For comparison of the eflect of varying the other reagents, additional samples were also treated by the procedure used on Sample G except for the changes footnoted at the bottom of Table VII.

may be used in this part the process. Various agents of this type are well known and commercially available in many i'crms. Typical illustrations include for example: many quarternary ammonium compounds such as cetyl pyridlnium bromide and the like; reaction products of polyalkylenepolyamines and fatty acids such as the reaction product diethylenetriamine and oleic acid; and, used illustratively in the following examples because of their typical action and comparatively greater availability, the long-chain fatty-acid amines of 14 or more carbon atoms. These amines are usually insoluble in water and to assist in distribution in the flotation feed are preferably used in the form of an acid salt such as the acetate, citrate or hydrochloride.

As in the iron flotation, the feed. 1. e., the rougher iron flotation tailing, before being subiected to concentration by i'roth flotation is conditioned with the promoter. This is quite important in obtaining optimum separation for the amount of reagent used. Whether this condi- Tnble VII Amayapercent Percent, P t 11,001, Percent, Distribum 100 0011 PH Wt. 1100 $2 3 0. 00 (Poor float-discanied) 0.00 0.0 01.41 13.01 0.100 11.00 0102 1.40 0.1 00.42 14.2; 0.10 12.00 0.110 2.00 2.1 01.11 13.00 0.10 11.03 0.100 0.00 0.0 00.10 13.01 0.003 11.01 0.010 0.00 0.00 01.31 13.01 0.000 11.10 0.000 0.00 3.3 10.10 10.02 0.001 10.00 0.000 0.00 10.00 10.00 0.011 10.00 0.011 0.00 00.00 0.000 0.004 0.00 01.00 0.01 0.05s

1 Snllonatc reagent re dispersibie and water-so nble suiionates.

laced by 1.23 lbs/ton 01 a 2-1 mixture of oil-soluble water Sulionate reagent :0 laced by 1.67 lbs/ton 01 11 mixture oi oil-soluble water-dispersible and wetersclu le sulfonates Repeat 0! sample K using 0.05 lbJtonof Acrofloet 31 as a both conditioning agent.

1 Repeat 0! sample G using 1.67 lbs/ton oi suli'onates 31 as a froth conditioning agent.

3 Repeat of sample M raising oil content to 1.54 lbs/ton and 0.10 1b.]ton oi Aerofloat i Repeat 0! sample M. raising oil content to 2.31 ibalton and 0.10 lbJton oi Aeroiioat 31.

INCREASING A1203 CONTENT OF PRODUCT The foregoing examples have been primarily concerned with the demonstration of that part of the present invention which is concerned with producing an iron-bearing concentrate of ferrous-metal silicates, thereby reducing the overall ferrous-metal content of the tailing. In most industrial uses of feldspar, it is desirable that the FezOs assay be less than 0.10%. In some of the above examples this grade has been produced, in others it has not. In addition a 16% or better content of A1003 is often required. While no special effort has been made in the foregoing examples to complete the production or a high grade spar concentrate, in actual practice this latter is an important part of the present process.

In general, the second stage in the present process comprises reversal of the first operation. It is primarily concerned with concentrating nonierrous metal silicates and non-ferrous metal aluminum silicates from the residual silica and ferrous-metal silicates in the iron flotation tailing. A cationic reagent is used to produce the promoting and/or concentrating action. In this way the cationic reagent i employed to best advantage on. a feed which is substantially free from slimes and which has been reduced in the iron-bearing substitutents.

Substantially any cationic type of promoter tioning is carried out at high or low solids is optional, although an operation at high solids tends to produce somewhat better results. Usually the amount required is between 0.25 and 0.75 lbs/ton although as much as 1.0 lb./ton or more may be occasionally required.

To assist in disseminating the cationic reagent, which is usually employed in comparatively small quantities, an oiling or diluting agent is also desirable in this operation. As in the iron flotation, the most practical oil is a light petroleum distillate such as kerosene or light fuel oil. The amounts used are usually about the same as in the iron flotation although this amount may not be actually required. From about 0.5-1.5 lbs/ton are usually suitable. As in the iron flotation, the

1 petroleum oil may be replaced with other organic 70 lower in concentration. Since it is a conditionduring the same conditioning ing agent, it is the primar reason for using a conditioning step, although, as noted, the latter also is helpful in disseminating the cationic reagent. 1

the same except that the hydrofluoric acid used was increasedto 3.33 lbs/ton. The results are shown in Table IX. Both the iron and alumina content are highly satisfactory;

Table IX i Per Cent Distribution Pegvtzent Per Cent Assays Original Feed 01' al Spar F e v Float A1101 mo; 41,0. r010. A110 B her Iron Tailr in? A 84.58 14. 55 0.053 70. 41 17.02 1 100.0 Spar Concentrate..- 01.00 10.50 0.00 73.03 14.74 00.75 Quartz Tailing 20.40 1.72 0. 035 2.48 3.18 0. 25 A i'rothing agent also is usually desirable. Any EXAMPLE 12 standard frothers such as natural or synthetic pine oil or the 78 carbon atomaliphatic alcohol i'rothers may be used alone or in mixtures. If so desired, they may be added directly to the cells The procedure of Example 10' was repeated on v in Example 7. The results are shown in the following. Table X.

Table '3 Per Cent Distribution Perwptent Per Cent Assays o hi ill/Bl Feed spar Feed Float 7 1 F 201 A1201 1 2 Rougher Iron Teil- 89. 72 15. 23 07 84. 79 21. ,72 100. 00 Spar Oonoentrate 65. 97 19. 80 09 81.07 18. 85 95. 01 Quartz Tellin n75 2.52 .04 3. 72 2.87 4. 39 during the flotation operatiombut for simplicity EXAMPLE 13 in operation they are preferably incorporated operation in which the hydrofluoric acid and the cationic promoter are added. Additional frother added after flotation has proceeded for some time is eifective in promoting the last traces of valuable mineral.

EXAMPLE In order to illustrate the feldspar flotation operation in the process of the present invention the rougher tail obtained in Example 4 above was dewatered to about 65% solids and conditioned for 1 minute with 0.77 lb./ton of fuel "011, 2.0 lbs/ton of 48% hydrofluoric acid. 0.07 lb./rton of of pine oil and 0.50 lb./ton of ootadecylamine acetate. The metallurgical results are shown in the following table:

.- for 15 seconds In order to illustrate the overall procedure, another sample of the same ore treated in Example 11 was ground to size for flotation feed. pulped with water to about solids, scrubbed with 0.13 lb. /ton of NaOH and deslimed hydraulically. The sands were then conditioned at about 60-70% solids with 0.67 lb./ton of H2804, 1.67 lbs/ton of a 3-1 mixture of oilsoluble, water-dispersible and water-soluble sulionated petroleum hydrocarbons; 2.31 lbs/ton of fuel oil and 0.05 lb./|ton of "Aerofloat 31".. The conditioned pulp was diluted to 29-30% solids, floated for 3 minutes and iron concentrate removed.

The rougher'iron' tailing was then conditioned for one minute at 26% solids with an additional 0.75 lb./ton of fuel oil, 1.33 lb'./ton of 48% hydro- Table VIII Assays Percent Percent Distribution an:

erg Bl riginal Wm] Fm F oat Feed A110; F630: Slog A1701 F6102 A110;

Rougherlron Telling. 89.89 14.22 0.11 70.50 70.33 38.22 100.00 Spar Coneentrate 67.82 -18. 54 0.13 69.34 78.09 33.98 98.44 Quartz Telling 22.00 0.89 0.05 98.56 1.24 4.24 1.50

Examrnr: 11 l-b./ton of octadecylamine ace As shown in Example 10, a satisfactory A1203 assay was obtained the F6203 content is a. little higher than usually I desired. Accordingly, the procedure of Example in good recovery. However,

10 was repeated on the rougher concentrate obtained in Example 5 above. The conditions were commercial alcoholic fluoric acid, 0.50

tate, 0.07 lb./|ton of pine oil and 0.03 l:b./ton of a .alcohol frother.

iron-bearing content of the ore is in thatfraction which is most easily reduced to small sizes. This can be taken advantage of in the present process by crushing the ore to 20 mesh, removing the +35 mesh fraction and subjecting only the 35 mesh fraction to froth flotation. This may be done in those cases where the +35 mesh sands are sufliciently high in aluminum and low in iron so that they may be mixed with the flotation concentrates .to produce saleable products, particularly when only the iron content requirement is to be met This is illustrated in the fol lowing example.

EXAMPLE 14 I A sample of feldspar ore contaminated with iron stainings, quartz and several mixed ironbearing silicates was crushed to about 20 mesh 55 and the crushed ore pulped with water to about 37% solids and scrubbed for 2 minutes with 1 lb. /ton of the caustic soda. It was then screened at 35 mesh, the +35 mesh fraction being retained and the 35 mesh fraction being deslimed hydraulically. The deslimed fraction was conditioned for 4 minutes at 65-70% solids with 1 lb./ton of sulfuric acid, 0.35 lb./ton of fuel oil and 1.0 lb./ton of mixed petroleum sulfonates (about 75% green acids). The conditioned pulp was diluted to about 20% solids and floated for 8 minutes with 0.02 lb./.ton of pine oil, 0.03 lb./ton of Aerofloat '31 and 0.10 lb./ton of a higher The rougher iron concentrate was removed. The rougher iron tailing was floated for 2 minutes with 0.02 lb./ton of pine oil, 3.0 lbs./ton of 48% hydrofluoric acid and 0.31 lb./ton of crude octodecylamine acetate. The results are shown in the following table.

' Table XI Aways, per cent Distrilggitcn, per

Percent w. 111,0 r 0, s10 (v v li i'a 2 Fe 100.00 10.11 0.10 70.00 100.00 R0 Iron Gone 12.62 1.76

85.70 10.05 15.13 80.07 10000 Re. Spar Con0 62. 67 19. 31 68.05 76.11 03.80 o1. Spar COIl0.-.... 50.38 20.10 0.00 00.10 70.33 87.33 Quartz Tail 22.03 3. 47 94. 40 4. 98 6.

From the foregoing it will be apparent that the Table XII process of the present invention represents a true combination of steps into a unitary whole. In so doing neither operation is pushed to its ex- 20 Percent Assaywemni Pei-mm; treme limit so far as that particular step is mm Weight 33. 33 cerned. By combining them a flexible procedure is obtained which enables the production of a o uniform product 0! hi h grade and in higher re- Pl l S ME5h 22.3% i223 8.1 1;? 35.32 igi covery than can 'be obtained by the practice of ffEf R 3 mm o m 66 g g-g; either alone. Msinus M0513 In treating the average feldspar ore in accordgbgg 33 L01 gag; ance with the present invention, the usual treat- FBldBPa' 33-34 0-031 6136 vM9 t 'r ii ment consists in reducing the ore to -20 mesh '30 gigs? fissure 7 3 24 o 017 95 9 as flotation feed. However it may be economlr fig g 'figfii j' 83-61 72432 cally advantageous in some cases to treat only F i spar 0110-- 70.10 10.89 0.053 70.35 the smaller sized fractions, for example, the 35 mesh particles, by flotation. This results in lowered reagent consumption. Often much of the 35 Iclaim'.

1. In a concentration by froth flotation of a feldspathic materiais ore, too low in A110: assay and too high in ferrous metals oxides and silicates, in which a pulp of the ore is floated with 40 an anionic promoter to produce an enriched feldspathic-materials tailing and a feldspathic-materials concentrate is floated from said tailing with a cationic promoter; the improved method of reducing the ferrous-metals silicates content which comprises the steps of pulping the ore with water; simultaneously conditioning the pulp with a sufficient amount of a member of the group consisting of the water-soluble acids and acid salts yielding H free acidic radicals in solution to produce a pH of from about 2.5-5.0 in the pulp at flotation density and with an eflective amount of a promoter selected from the group of sulfonated petroleum hydrocarbons obtained in the manufacture of lubricating oil stocks consisting of the oil-soluble, water-dispersible sulfonates of the mahogany type, the water-soluble sulfonates of the green type and mixtures thereof; subjecting the condi- JlOIlBd pulp to froth flotation and removing the flotation concentrate. 2. A process according to claim 1 in which the are after pulping with water is scrubbed with about 0.1 ib.-1.0 lbs. per ton of caustic soda and then deslimed before being conditioned with the reagents.

3. A process according to claim 1 in which the ore after pulping with water is scrubbed with about 0.1-1.0 lbs. per ton of caustic soda and then deslimed before being conditiored with the reagents, the conditioning being carried out at a solids content of about 30-70% and the conditioned pulp being diluted to flotation density before being subjected to froth flotation.

4. A process according to claim 1 in which the 7 promoter comprises a mixture of from about 18 50-85% water-soluble and 15-50% oil-soluble, Number Name Date water-dispersible sulfonated petroleum hydrocar- 2,410,376 Booth Oct. 29, 1946 bons. v 2,410,377 Booth Oct. 29, 1946 ELMER WILLIAM GIESEKE. 5 OTHER REFERENCES REFERENCES CITED Bulletin of American Ceramic Society, volume The following referenc s are of record in the g 1939 pages file of this patent: an UNITED STATES PATENTS m Number Name Date 2,289,741 Tartaron July 14, 1942 Certificate of Correction Patent No. 2,483,192 September 27, 1949 ELMER WILLIAM GIESEKE It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 8, line 24, strike out K 0 4.59 column 12, line 74, for the words used in read used is; column 14, line 44, for 60-70% read 65-70% and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office. Signed and sealed this 7th day of February, A. D. 1950.

THOMAS F. MURPHY,

Assistant G'ommz'ssz'oner of Patents. 

